Revisiting the 49ers' strategy (again)

Posted by ESPN.com's Mike Sando

Thanks much to John Morgan of Field Gulls for engaging my earlier analysis on how the Seattle offense functioned against a 49ers defense that left five defensive backs on the field even when Seattle played with fewer than three receivers.

The implication in questioning the 49ers' strategy was logical. Why would a team leave five defensive backs on the field even when the opponent was running the ball effectively? The 49ers did it, coach Mike Nolan said, in part because they thought constantly matching Seattle's personnel would put them at a disadvantage.

John wondered why I would isolate only first-half plays, suggesting I might have done that to enhance my argument. The reason I didn't look at the second half was because I ran out of time the other night and figured 31 plays would give us a pretty good idea.

This morning I looked at the second half as well. I decided to look at every Seahawks drive except the last one, when field position convinced Seattle to play for overtime (some players and coaches look for tendencies through only the first three quarters of games because fourth-quarter play calling reflects point differential more than what an offense likes to do).

In any event, here are the findings based on the Seahawks' first 66 plays (see chart at bottom):

Seattle averaged 3.6 yards per carry with three first downs on eight carries from its base offense (2RB,2WR,1TE). That figure grew to 4.5 yards per carry with zero first downs on four carries from a variation of its base offense (1RB,2WR,2TE)

As John notes, this could be considered "successful" running of the football. It's also true that Seattle averaged more yards per carry running from three-receiver groupings, and the 49ers' strategy succeeded in foiling the Seattle passing game, which was the point all along.

Seattle averaged 6.1 yards per carry with two first downs on seven rushes from its primary three-receiver grouping (1RB,3WR,1TE). The Seahawks averaged 5.8 yards per carry with three first downs from their secondary three-receiver grouping (2RB,3WR).

I also broke down Seattle's passing offense. The Seahawks were most successful throwing from their base offense. They struggled throwing from three-receiver groupings.
Specifically, Seattle averaged 9.5 yards per pass attempt with eight first downs on 13 plays from its base offense (2RB,2WR,1TE).

The Seahawks averaged 5.2 yards per attempt with three first downs and one interception on 13 pass plays from their primary three-receiver grouping (1RB,3WR,1TE).

Seattle averaged 1.0 yard per attempt with one first down and one interception on four pass plays from its secondary three-receiver grouping (2RB,3WR).

Seattle averaged zero yards per attempt with zero first downs on four pass plays from its "Tiger" personnel grouping (1RB,2WR,2TE).

Of these 66 plays I looked at, the Seahawks ran 35 with three receivers, 29 with two receivers, one with one receiver and one with four receivers. They ran 37 plays with two running backs and nine plays with two tight ends (including one play with two backs and two tight ends, resulting in a 1-yard touchdown run).

For those interested in pursuing this further, I'll provide a chart that summarizes Seattle's production running and passing across personnel groups for these 66 plays. I've shaded the rows showing the two- and three-receiver groupings. I've bolded the columns showing the number of receivers and yards per carry.